Automatic analyzing apparatus

ABSTRACT

An automatic analyzing apparatus has an analysis section including an immunity analysis unit and a biochemical componential analysis unit. A sample rack which has undergone the immunity componential analysis is horizontally fed by a rack feeding mechanism from a position confronting the inlet of a rack stationing section to a position near the outlet of the rack stationing section, so that the sample rack is directly moved to a return line, while skipping over the rack stationing section, so as to be efficiently returned to the analysis section and subjected to a subsequent biochemical analysis. A sample rack that needs reexamination by an identical analysis unit is also returned in the same efficient way.

This is a continuation application of U.S. patent application Ser. No.10/445,918 filed on

May 28, 2003 (now U.S. Pat. No. 7,300,628), the entire disclosure ofwhich is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention broadly relates to an automatic analyzingapparatus which automatically performs componential analysis of samplessuch as blood or urine that are extracted from living bodies and, moreparticularly, to an automatic analyzing apparatus which shifts samplesfrom sample vessels in a sample rack into an analyzing section foranalysis, and which performs reexamination as required.

2. Description of the Related Art

Automatic analyzing apparatuses of the kind described are capable ofquickly analyzing a lot of samples extracted from living bodies and,therefore, are widely used in medical centers and clinical examinationcenters. On the other hand, there is an increasing demand for furtherincrease of the throughput per unit time and further diversification ofanalysis items. In order to cope with demand, a module-type analyzingapparatus has been proposed which incorporates a plurality of analyzingmodules connected to a transfer line which transfers sample racksaccommodating sample vessels. Another type of automatic analyzingapparatus has also been proposed which has a mechanism for shifting aselected sample rack back to the inlet or upstream end of the transferline through a return line, for the purpose of reexamination which isnecessary when, for example, the density of the samples failed to fallwithin the range measurable by the apparatus. This type of automaticanalyzing apparatus has been disclosed in and known from JP-A-10-213586.

SUMMARY OF THE INVENTION

In the automatic analyzing apparatus disclosed in JP-A-10-213586, sampleracks containing matters which need not be re-examined, e.g., a controlsample, a standard sample, and a cleaning fluid, are registered at acontrol section of the apparatus as being non-reexamination sample racksthat need not be subjected to reexamination. A non-reexamination rackupon reaching the terminal end of the transfer line is directed to arack collecting section, by means of a first sorting unit which isinstalled at the terminal end of the transfer line, whereas other sampleracks containing sample samples are all directed to a rack stationingsection composed of a U-shaped line. A second sorting unit, which isinstalled downstream of the first sorting unit, operates to selectsample racks to be subjected to reexamination out of the racks that arestationed in the rack stationing section and directs the selected sampleracks to the return line, while directing other racks that need not bereexamined to the rack collecting section.

Thus, sample racks that were determined before reaching the firstsorting unit as being unnecessary to be reexamined are also temporarilystationed in the rack stationing section.

When the automatic analyzing apparatus employs a biochemical analyzeralone connected to the transfer line, probability of occurrence of theneed for reexamination is quite low, so that the above-describedarrangement is usable without substantial risk of trouble. This,however, is not true with an automatic analyzing apparatus of the typewhich employs both an automatic immunity analyzer and an automaticbiochemical analyzer that are connected to an identical transfer line.More specifically, this type of automatic analyzing apparatus tends tosuffer from impairment of reliability due to carry-over, i.e.,contamination of a sample with another kind of sample, which may occurthrough the use of a dispensation device. One solution to this problemis to conduct an immunity analysis prior to biochemical analysis. Thissolution, however, tends to cause a delay in the finalization of theexamination report because all the sample racks having vesselscontaining samples are temporarily stationed at the rack stationingsection.

It is also to be noted that the total analyzing time may considerablyshortened even in the case of the automatic analyzing apparatus of thetype which employs either one of the immunity analyzer or thebiochemical analyzer, if the apparatus is arranged such that the sampleracks, which have been determined before reaching the first sorting unitas being not necessary to be reexamined, are directly sent to the rackstationing section.

Accordingly, it is an object of the present invention to provide anautomatic analyzing apparatus with which automatic analysis can beconducted in a shorter time than by known apparatuses.

To this end, in accordance with one aspect of the present invention,there is provided an automatic analyzing apparatus, comprising: ananalysis section for examining samples extracted from sample vesselsaccommodated in sample racks; a transfer line for transfering the sampleracks to the analysis section and for further transfering the sampleracks to an outlet after the extraction of the samples; a rack supplyingsection for supplying the sample racks to the transfer line; a rackstationing section for stationing sample racks which have possibility ofbeing subjected to a reexamination; a rack collecting section foraccommodating the sample racks with which the examination has beenfinished; a return line along which the sample racks that need to bereexamined back to the analysis section; a first rack sorting sectionfor receiving the sample racks transfered by the transfer line, thefirst rack sorting section directing sample racks that have to awaitdetermination as to the necessity for the reexamination to thestationing section, while directing sample racks that do not have toawait the determination to a second rack sorting section; wherein thesecond rack sorting section selects, from among the sample racks whichhave been received from the first rack sorting section and which neednot await the determination, a sample rack determined as necessitatingthe reexamination and directing the selected sample rack to the returnline, while directing the sample racks with which the examination hasbeen finished to the rack collecting section, the second rack sortingsection also directing a sample rack that needs to be reexamined fromamong the sample racks which have been stationed in the stationingsection to the return line, while directing sample racks that need notbe reexamined to the rack collecting section.

In accordance with another aspect of the present invention, there isprovided an automatic analyzing apparatus, comprising: an analysissection for examining samples extracted from sample vessels accommodatedin sample racks; a transfer line for transfering the sample racks to theanalysis section and for further transfering the sample racks to anoutlet after the extraction of the samples; a rack supplying section forsupplying the sample racks to the transfer line; a rack stationingsection for stationing sample racks which have possibility of beingsubjected to a reexamination; a rack collecting section foraccommodating the sample racks with which the examination has beenfinished; a return line along which the sample racks that need to bereexamined back to the analysis section; a first rack sorting sectionfor receiving the sample racks transfered by the transfer line, thefirst rack sorting section directing sample racks that have to awaitdetermination as to the necessity for the reexamination to thestationing section, and selecting, from among the sample racks that neednot await the determination, sample racks that do not need thereexamination and directing the selected sample racks to the collectingsection, while directing the sample racks that need the reexamination toa second rack sorting section; wherein the second rack sorting sectiondirects the sample racks that need the reexamination received from thefirst rack sorting section to the returning line, the second racksorting section also selecting, from among the sample racks stationed inthe stationing section, sample racks that need the reexamination anddirecting the selected sample racks to the return line, while directingthe sample racks that do not need the reexamination to the collectingsection.

In accordance with still another aspect of the present invention, thereis provided an automatic analyzing apparatus, comprising: an analysissection for examining samples extracted from sample vessels accommodatedin sample racks; a transfer line for transfering the sample racks to theanalysis section and for further transfering the sample racks to anoutlet after the extraction of the samples; a rack supplying section forsupplying the sample racks to the transfer line; a rack stationingsection for stationing sample racks which have possibility of beingsubjected to a reexamination; a rack collecting section foraccommodating the sample racks with which the examination has beenfinished; a return line along which the sample racks that need to bereexamined back to the analysis section; a first rack sorting sectionfor receiving the sample racks transfered by the transfer line, thefirst rack sorting section directing sample racks that have to awaitdetermination as to the necessity for the reexamination to thestationing section, while directing sample racks that need thereexamination to the return line and directing sample racks that do notneed the reexamination to the rack collecting section; and a second racksorting section for selecting, from among the sample racks stationed inthe stationing section, sample racks that need the reexamination anddirecting the selected sample racks to the return line, while directingthe sample racks that do not need the reexamination to the collectingsection.

The described arrangements are particularly suitable for an automaticanalyzing apparatus of the type which has both an automatic immunityanalysis section and an automatic biochemical analysis section which areconnected to a common transfer line, wherein the automatic immunityanalyzing section performs an immunity componential analysis fordetermining whether a specific antigen or a specific antibody iscontained in a sample, i.e., a sample, while the automatic biochemicalanalysis section which performs a biochemical componential analysis.

The present invention, when incorporated in this type of automaticanalyzing apparatus, permits the samples after the immunity analysis tobe quickly sent for the subsequent biochemical analysis through thereturn line while skipping over the stationing section, thuscontributing to the shortening of the total analytic processing time.

Preferably, each of the automatic analyzing apparatuses describedheretofore further comprises a registration section in which informationas to the necessity for the reexamination for each sample rack has beenregistered; and a control section for controlling the operation of therack sorting sections in accordance with the registered information.

The stationing section may be configured to have a receiving area forreceiving the sample racks from the inlet of the stationing section anda delivery area through which the sample racks are delivered to theoutlet of the stationing section after lapse of a stationing period, thereceiving area and the delivery area being arranged to provide asubstantially U-shaped path of transfer of the sample racks.

The above and other objects, features and advantages of the presentinvention will become clear from the following description of thepreferred embodiments taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of the general arrangement of anautomatic analyzing apparatus embodying the present invention;

FIG. 2 is an illustration of a portion of a known automatic analyzingapparatus, showing a path along which sample racks are transfered whenreexamination is necessary;

FIG. 3 is an illustration of a path of transfer of sample racksimplemented in an automatic analyzing apparatuses of the first aspect ofthe present invention, in different modes of operation thereof;

FIG. 4 is an illustration of a path of transfer of sample racksimplemented in an automatic analyzing apparatuses of the second aspectof the present invention, in different modes of operation thereof; and

FIG. 5 is an illustration of a path of transfer of sample racksimplemented in an automatic analyzing apparatuses of the third aspect ofthe present invention, in different modes of operation thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows general arrangement of an automatic analyzing apparatuswhich is an embodiment of the present invention. This automaticanalyzing apparatus is of the type known as a hybrid apparatus whichcombines both an automatic biochemical analyzer 6 and an automaticimmunity analyzer 14. A plurality of sample racks 2 are arrayed in arack supplying section 1 and are transferred to a transfer line 3. Theracks 2 are transfered by the transfer line 3 past a recognition section4 having a recognition device 5 which may be, for example, a reader forreading identifiers such as bar codes provided on sample vesselsaccommodated in each sample rack 2, whereby each sample is identified bya rack number and a sample vessel number. The sample rack number and thesample vessel number recognized by the recognition device aretransmitted to a control section 33. Analysis instructions includinginformation concerning items of analysis to be performed on the samplesin sample vessels in each sample rack 2 have been given from anoperating section to the control section 33, in relation to samplereceipt numbers. The control section 33 then checks up the sample vesselnumbers with the sample receipt numbers to find the kind of analysisitem to be performed on the sample vessels, and determines thedestination of each sample rack 2 according to the item of the analysisto be performed. The information including the item of the analysis andthe destination of the sample racks 2 are stored in a memory section 34so as to be used in the analytical processing executed on the sampleracks 2.

An emergency rack supplying section 46 is provided upstream of the racksupplying section 1. When a sample rack 2 is placed on the emergencyrack supplying section 46 while other sample racks are stationed at therack supplying section 1, the rack 2 on the emergency rack supplyingsection 46 is transferred to the transfer line 3 in preference to theracks on the rack supplying section 1.

The automatic immunity analyzing section 14, which is arranged along thetransfer line 3, has the following components or elements: a samplingarea 16 which receives the sample racks 2 from the transfer line 3 andreturns the sample racks 2 after a sampling treatment back to thetransfer line 3; a reaction disc 18 which allows and promotes a reactionbetween the sample and a reagent in each of a plurality of reactionvessels arranged along a circle, according to the item of analysis to beperformed; a reaction vessel feeding mechanism 32 for feedingindependent reaction vessels one by one to the reaction disc; a reagentdisk 19 operative to locate each of reagents to be used for a variety ofanalysis items at a reagent sucking position; a reaction mixture suckingmechanism 27 for introducing the reaction mixture formed as a result ofthe reaction in each reaction vessel into a measuring unit; a measuringsection in which an electrical potential is given to an activatingelectrode as to cause the reaction mixture to illuminate, and theluminous intensity is measured; a sample dispensation mechanism 17 fordispensing samples from the sample vessels in the sampling area 16 intothe reaction vessels in the reaction disc 18; and a reagent dispensationmechanism 20 which dispenses reagents from reagent bottles in thereagent disk 19 into the reaction vessels in the reaction disc 18according to the items of the analysis to be performed.

The automatic biochemical analyzing section 6 has the followingcomponents or elements: a sampling area 8 which receives the sampleracks 2 from the transfer line 3 and returns the sample racks 2 after asampling treatment back to the transfer line 3; a reaction disc 10 whichallows and promotes a reaction between the sample and a reagent in eachof a plurality of reaction vessels arranged along a circle, according tothe item of analysis to be performed; a reagent disk 11 operative tolocate each of reagents to be used for a variety of analysis items at areagent sucking position; a multi-wavelength spectrophotometer formeasuring absorbance of the reaction mixture of the sample and a reagentformed in each reaction vessel; a sample dispensation mechanism 17 fordispensing samples from the sample vessels in the sampling area 8 intothe reaction vessels in the reaction disc 10; and a reagent dispensationmechanism 12 which dispenses reagents from reagent bottles in thereagent disk 11 into the reaction vessels in the reaction disc 10according to the items of the analysis to be performed.

Each sample rack 2 to be subjected to an analytical examination by theautomatic immunity analyzing section 14 or by the biochemical analyzingsection 6 is shifted from the transfer line 3 to the sampling area 8 orto the sampling area 10, by means of a rack pickup mechanism 7 or a rackpickup mechanism 15. The sample racks 2 thus shifted are moved to asampling position in the sampling area 8 or the sampling area 16, wheredispensation nozzles of the sample dispensation mechanism 9 or thesample dispensation mechanism 17 is inserted into the desired samplevessels, for the dispensation of the sample into the reaction vessels.

After the extraction of the samples for all the analysis items under theanalysis instruction, the sample racks 2 are moved to a position where arack ejection mechanism 13 or a rack ejection mechanism 21 is disposed,and are shifted back onto the transfer line 3 by means of the rackejection mechanism. Each sample dispensed into the reaction vessel onthe reaction disk 10 or the reaction disc 18 is made to react with anagent which is dispensed by the reagent dispensation mechanism 12 or bythe reagent dispensation mechanism 20. After elapse of a predeterminedtime, the measurement is conducted so that measurement data is obtainedfor each of the analytical items. The analytical measurement data thusobtained is delivered to the control section 33. The control section 33then checks up the analytical measurement data with a predeterminedstandard data to confirm whether the analytical measurement data isacceptable. Upon determining that a reexamination is necessary due tofailure to meet the standard, the control section 33 operates to informthe memory section 34 of the fact that the reexamination is necessary,together with the information indicating the sample rack number and thesample vessel number with which the failure has been detected. Thecontrol section 33 also controls the operation of a later-mentioned racksorting mechanism 22 at proper timings. Conversely, the sample racks 2that were determined as being unnecessary to be reexamined aretransfered to and accommodated in a rack accommodating section 23. Afterthe measurement is completed, the results are displayed on a displaysection 36 and are stored in the memory section 34.

A description will now be given of a conventional route or path alongwhich the sample racks to be subjected to reexamination are transfered,with specific reference to FIGS. 1 and 2.

The rack sorting mechanism 22 has the following components: a reciprocalrack pushing mechanism 40 which in its forward stroke pushes the samplerack 2 into a rack stationing section 24; a rack feeding mechanism 41having claws which are moved by, for example, an endless belt so as topush the trailing ends of the sample racks 2; and a retractable rackstopper 45 having a solenoid-actuated member which when projected abutsthe leading end of the sample rack 2 thereby preventing further movementof the sample rack 2. A rack take-up mechanism 28 includes a rackforwarding mechanism which pushes the trailing ends of the sample rackswhich are carried by a forwarding line 26 and which need not bereexamined, so as to transfer these racks 2 to a belt of anaccommodation line 47. A rack return mechanism 43, which is provided atthe inlet of a return line 30, has claws that are moved by, for example,an endless belt so as to push the trailing ends of the sample racks 2which have been forwarded by the forwarding line 26 and which are to besubjected to reexamination, thereby transferring these racks 2 to thereturn line 30. Sensors for confirming positions of the racks aredisposed at suitable positions along the path of transfer of the sampleracks.

As explained before in connection with FIG. 1, a decision has been madeby the control section 33 as to whether each sample rack 2 on theforwarding line 26 is to be sent to the rack accommodating section 23 orto the rack stationing section 24, before the sample rack 2 reaches therack sorting section 22.

When the control section 33 has determined that the sample rack 2 is tobe sent to the rack accommodating section 23, the retractable rackstopper 45 is kept inoperative. After absence of any rack at the inletof the rack stationing section 24 has been confirmed by a rack sensor74, the rack feeding mechanism 41 is activated so as to send the rack 2to the inlet of the rack stationing section 24. Then, after confirmingabsence of any rack at the outlet of the rack stationing section 24 by arack sensor 75, the rack take-up mechanism 28 is activated so that therack 2 is moved onto the accommodation line 47 past the outlet of therack stationing section, on condition that absence of any rack on theaccommodation line 47 has been confirmed by a rack sensor 77. The rack 2is then transfered by the accommodation line 47 to the inlet of the rackaccommodation section 23, and is pushed by a rack pushing mechanism 29into the rack accommodation section 23, so as to be stored in thelatter.

Conversely, when the control section 33 has determined that the samplerack 2 is to be brought to the rack stationing section 24, theretractable rack stopper 45 is activated so that the sample rack 2 isstopped at the inlet of the rack stationing section 24, and the rackpushing mechanism 40 is activated to push the rack 2 into the rackstationing section 24. Safe receipt of the rack 2 by the rack stationingsection 24 is confirmed by a rack sensor 70 which is installed at theinlet of the rack stationing section 24. A plurality of sample racks 2are thus successively brought into the rack stationing section 24. Whenno sample rack 2 is brought to the rack sorting mechanism 22 until arack sensor 71 senses any sample rack or until a predetermined period oftime lapses, a batch of the sample racks 2 is fed by a rack feedingmechanism 42 to a rack delivery position 48. After absence of any samplerack on a forwarding arm 44 of the forwarding line 26 is confirmed by arack sensor 72, a rack shifting mechanism 25 is activated so that thesample racks 2 that have been sent to the rack delivery position areshifted to and grasped by the rack forwarding arm 44. If a determinationhas been made as to whether the sample rack 2 grasped by the forwardingarm 44 it to be subjected to the reexamination, the sample rack 2 isimmediately forwarded to the rack take-up mechanism 28 or to the returnline 30. The sample rack 2 when forwarded to the return line 30 istransferred by a rack returning mechanism 31 onto the transfer line, soas to be sent to the analysis section. If the determination as to thenecessity of the reexamination has not been made, the sample rack isstationed.

FIG. 3, shows an automatic analyzing apparatus which is a modificationof the apparatus shown in FIG. 1, wherein a pair of rack sortingmechanisms are provided in order to achieve more efficient forwarding ofthe sample rack to be reexamined to the return line.

The sample racks that have undergone the measurement in the analysissection includes sample racks 2 which are still awaiting thedetermination to be done by the control section 33 as to the necessityof the reexamination. The retractable rack stopper 45 in a first racksorting mechanism 37 is activated, and the sample racks which areawaiting the determination are moved to the rack stationing section 24by the operation of the rack pushing mechanism 40. Among these racksstationed in the rack stationing section 24 and waiting for thedetermination, a sample rack which is then determined by the controlsection 33 as necessitating the reexamination is transfered to theforwarding line 26 along the route which was described before inconnection with FIG. 2. This sample rack 2 is then grasped by the rackforwarding arm 44 and forwarded along the forwarding line so as to bedelivered from the outlet 49 of the forwarding line to the inlet 73 ofthe return line. The sample rack 2 is then horizontally pushed by therack feeding mechanism 43 onto the return line 30 and is transfered bythe endless belt of the return line 30 to the outlet of the return line30, so as to be delivered to the analysis section.

Conversely, a sample rack 2 among the racks 2 stationed in the rackstationing section 24, on which the control section 33 then determinesthat the reexamination is unnecessary, is forwarded from the forwardingline 26 to the outlet 49 of the forwarding line by the forwarding arm44. This sample rack 2 is then horizontally pushed by the rack take-upmechanism 28 onto the accommodation line 47 and is further pushed by therack pushing mechanism 29 so as to be accommodated by the rackaccommodation section 23.

Meanwhile, a sample rack 2, which has already been determined asnecessitating the reexamination, is horizontally transfered from thefirst rack sorting mechanism 37 directly to a second rack sortingmechanism 38, by the operation of the rack feeding mechanism 41. A rackfeeding mechanism 39 pushes the trailing end of this sample rack 2 so asto horizontally move this sample rack 2 to a position confronting theoutlet 49 of the forwarding line 26. In the meantime, the forwarding arm44 has been moved to the position confronting the outlet 49 of theforwarding line. The sample rack 2 is then forwarded from this positionto the inlet 37 of the return line. The rack return mechanism 43 pushesthe head of the sample rack 2 so as to move the latter onto the transferbelt of the return line 30. The sample rack 2 is then transfered by thetransfer belt to the outlet of the return line, and is delivered to theanalysis unit for the reexamination.

Among the sample racks that have been sent from the first rack sortingmechanism 37 to the second rack sorting mechanism 38, a sample rack 2 onwhich the control section 33 has determined that the reexamination isunnecessary is horizontally pushed by the rack feeding mechanism 39 ontothe accommodation line 47, and is further pushed by the rack pushingmechanism 29 into the rack accommodation section 23 so as to be storedin this section 23.

The rack sensor 74, 75, 76 and 77 are operative to detect arrival ofeach sample rack 2 at proper transfer position, as well as presence orabsence of the sample rack at proper position.

FIG. 4 shows an arrangement which employs a pair of rack sortingmechanisms as in the case of the automatic analyzing apparatus of FIG.3, and offers more efficient storage of the sample racks in the rackaccommodation section than done by the arrangement shown in FIG. 3.

In the arrangement shown in FIG. 4, the same method of transfer as thatdescribed before in connection with FIG. 3 applies both to the sampleracks which are awaiting reexamination and the sample racks which havebeen determined as necessitating the reexamination. However, the samplerack 2 which has been determined as not necessitating reexamination ishorizontally fed by the rack feeding mechanism 41, directly from thefirst rack sorting section to the accommodation line 47, skipping overthe rack stationing section 24 and the second rack sorting section. Thesample rack 2 is then pushed by the rack pushing mechanism 29 into theaccommodation section 23, so as to be stored in the latter.

FIG. 5 shows an arrangement which employs a pair of rack sortingmechanisms as in the cases of the arrangements shown in FIGS. 3 and 4,and which enables forwarding of the sample racks directly to the returnline by the cooperation of these rack sorting mechanisms.

Upon reaching the first rack sorting section 37, a sample rack 2 whichhas already been determined as necessitating the reexamination isdirectly fed to the return line 30 y the operation of the rack feedingmechanism 39 of the first rack sorting mechanism 37. Thus, the samplerack 2 need not be sent to the second rack sorting mechanism 38, wherebya quicker forwarding of the sample rack to the return line isimplemented. In this arrangement, the sample racks 2 which are awaitingthe determination as to the necessity of reexamination are handled andtransfered in the same way as that described before in connection withFIGS. 2, 3 and 4. The method of transfer of the sample racks determinedas not necessitating the reexamination is the same as that describedbefore with reference to FIG. 4.

Each of the automatic analyzing apparatuses described in connection withFIGS. 3 to 5, as well as the apparatus shown in FIG. 1, can be used insuch a way that a biochemical analysis is performed following animmunity analysis. In such a case, the sample racks are transfered alongthe same route or path as that used for the transfer of the sample racksnecessitating reexamination in the apparatuses heretofore described.More specifically, instruction information that a sample rack 2 is to besubjected both to the immunity analysis and the biochemical analysis hasalready been recorded in a medium, by the time the sample rack 2 entersinto the rack supplying section 1. In accordance with this instructioninformation, the control section 33 produces instructions so that thesample rack 2 with which the immunity analysis has been finished isforwarded to the biochemical analysis section. More specifically, thesample rack 2, which has undergone the measurement in the immunityautomatic analysis section 14 and which is to be sent to the biochemicalautomatic analysis section 6, is transfered to the first rack sortingmechanism 37 through the transfer line 3. The sample rack 2 is thentransfered to the return line, along a path which is the same as thattracked in the arrangements shown in FIGS. 3 to 5 by the sample rack 2that has been determined as necessitating reexamination before arrivingat the first sorting mechanism. The sample rack 2 is then transfered tothe automatic biochemical analysis section 6 along the route which isthe same as that described before.

According to the present invention described in claim 1, it is possibleto efficiently transfer the sample racks which await determination as tothe necessity of reexamination, as well as the samples that needreexamination and the samples that do not need the reexamination, byvirtue of the cooperation of the pair of rack sorting sections.

According to the invention described in claim 2, an advantage in thatthe sample racks can be transfered from the upstream rack sortingmechanism directly to the rack accommodation line, thus achieving moreefficient storage of the sample racks.

According to the invention described in claim 3, an advantage in thatthe sample racks can be transfered from the upstream rack sortingmechanism directly to the return line, thus achieving more efficientreexamination of the samples.

According to the present invention described in claim 4, it is permittedthe samples after the immunity analysis to be quickly sent for thesubsequent biochemical analysis through the return line while skippingover the stationing section, thus contributing to the shortening of thetotal analytic processing time.

1. An automatic analyzing apparatus, comprising: a control sectionoperatively connected so as to control operations of the analyzingapparatus; a transfer line for transferring sample racks; an analysissection connected to said transfer line by a rack pickup mechanism, forreceiving sample racks from said transfer line and examining sampleextracted from sample vessels accommodated in said sample racks; a rackejection mechanism in said analysis section connected to said transferline for transferring said sample racks from said analysis section backto said transfer line after extraction of said samples; a rackstationing section connected to said transfer line downstream from saidanalysis section for stationing sample racks which have a possibility ofbeing subjected to reexamination; a rack collecting section connected tosaid rack stationing section for accommodating the sample racks withwhich the examination has been finished; a return line along which thesample racks that need to be reexamined are returned back to saidanalysis section, said return line having an inlet for receiving thesample racks from said rack stationing section; a first rack sortingsection located downstream from an outlet of said transfer line forreceiving said sample racks transferred by said transfer line, saidfirst rack sorting section being connected to said rack stationingsection and to said return line, and directing sample racks that have toawait determination as to the necessity for the reexamination to saidrack stationing section, while directing sample racks that have finishedexamination to said rack collecting section, said first rack sortingsection also receiving sample racks which have already been determinedas necessitating the reexamination; and a second rack sorting sectionconnected to said first rack sorting section downstream therefrom by arack feeding mechanism and connected to said inlet of said return lineand to said rack stationing section and said rack collecting section,which selects, from among the sample racks which have been received atsaid rack stationing section, a sample rack determined as necessitatingthe reexamination and directs the selected sample rack to said inlet ofsaid return line, said second rack sorting section also directing asample rack that need not be reexamined to said rack collecting section;and wherein said rack feeding mechanism transfers the sample racks thatrequire reexamination from said first rack sorting section directly tosaid return line when the sample racks first reach said first racksorting section and transfers the sample racks that have finishedexamination from said first rack sorting section to said rack collectingsection by a rack accommodation line connected to said first racksorting section through said second rack sorting section.
 2. Anautomatic analyzing apparatus according to claim 1, wherein saidanalysis section comprises an immunity analysis unit which performs animmunity componential analysis and a biochemical analysis unit whichperforms a biochemical componential analysis, and a sample rack whichfinishes an analysis in said immunity analysis unit is carried by saidtransfer line and directed to said return line by said first racksorting section, and is transferred to said biochemical analysis unit bysaid return line.
 3. An automatic analyzing apparatus according to claim1 further comprising: a registration section in which information as tothe necessity for the reexamination for each sample rack has beenregistered; and wherein said control section controls the operation ofsaid rack sorting sections in accordance with the registeredinformation.
 4. An automatic analyzing apparatus according to claim 1,wherein said rack stationing section has a receiving area for receivingthe sample racks from an inlet of said rack stationing section and adelivery area through which said sample racks are delivered to an outletof said rack stationing section after completion of a stationing period,said receiving area and said delivery area being arranged to provide asubstantially U-shaped path of transfer of said sample racks.